Preterm birth results in significant cognitive disability at school age. MRI studies paired with neuropsychological testing of very low birth weight infants at school age demonstrate significant cognitive handicap as well as correlative morphologic anomalies. Circulatory disturbances and oxygen deprivation are the two major causes of neurodevelopmental impairments in these children. We hypothesize that the chronic sublethal hypoxia that accompanies preterm birth disrupts the developmentally programmed maturafion of the preterm brain. This injury results in the inappropriate phasing of both eariy and late developmental events, with consequenfial long-term changes in corticogenesis and behavior. The development of a clinically-relevant model of preterm birth requires selection of an animal model that is: (1) faithful to the developmental stage of the infants studied; (2) documentation that the injury studied produces neuropathologic alterations: and (3) provides evidence of a correlation between injury and behavioral outcome. An overarching goal of this Program Project, as exemplified in the four invesfigafional projects, is to understand the cellular and molecular basis of this complex pathology. The goal of Core B, is to oversee the experimental exposure to hypoxia and enrichment interventions required by all projects. Core B will also add additional data both independently, and cooperatively, on the behavioral capacity of experimental and transgenic mice and on the maturation of connectivity using Diffusion Tensor Imaging (DTI) imaging. Finally, the Core will provide stafisfical consultafion to all projects, and will aid in data analysis using a comprehensive ensemble of biostafistical tools.